Effect of polyethylenimine on hydrolysis and dispersion properties of aqueous Si3N4 suspensions

Xinwen Zhu, Tetsuo Uchikoshi, Tohru S. Suzuki, Yoshio Sakka*


研究成果: Article査読

42 被引用数 (Scopus)


The roles of polyethylenimine (PEI) in the hydrolysis and dispersion properties of aqueous Si3-N4 suspensions were studied in terms of the hydrolysis, adsorption, electrokinetic, and rheological measurements. It was found that the pH change of the suspensions in the acidic environment could be minimized in the presence of ≥ 0.5 dwb% PEI. The ammonia and oxygen measurements suggest that this phenomenon is primarily attributed to the buffer mechanism generated by the ionized PEI, instead of the protection mechanism. The constant pH enables the suspensions to retain a better stability with time at acidic pH. The adsorption of PEI on Si3N4 is a high-affinity type at highly basic pH, but is a low-affinity type at acidic pH. As the PEI amount increases, the adsorption shifts the isoelectric point (IEP) of Si3N4 from pH 5.9 to pH ∼11 until complete coverage is attained. The stability of Si3N4 suspensions is found to depend strongly on the saturated adsorption of PEI, which is as a function of the pH and PEI amount. Once the saturated adsorption limit is reached, the excess free PEI molecules become more detrimental to the stability with increased solid loading. The stabilization mechanisms of Si 3N4 suspensions by PEI were discussed in detail.

ジャーナルJournal of the American Ceramic Society
出版ステータスPublished - 2007 3月

ASJC Scopus subject areas

  • セラミックおよび複合材料
  • 材料化学


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